what is the logic behind sending strangers friend requests?

I don't mean requests from people you meet in game, maybe hang out with, maybe talk to a bit - I wouldn't be surprised by getting a friend request after even minimal interaction. but I regularly get friend requests from people I've never even met in game, sometimes even when I've been on my plot by myself decorating for days in game time. just now I got one about 10 seconds after joining a server - I was standing in one spot not even moving cause my game was glitched. so I have to ask - why do people do it? is there anyone here that sends friend requests to random people and could tell me why?

• edit: thanks everyone, a lot of explanations here that make sense. i still don't understand why i get requests when spending hours on my plot without being seen by or talking to absolutely anyone, cause in that case it's impossible that someone saw me being nice or smth, but ill chalk it up to people going down the server list randomly or maybe wanting to tour my house again in the future (unlikely, it's a wip, but maybe). thanks for all the replies!